8 The probability is 0.4 that a traffic fatality involves an intoxicated oralcohol-impaired driver or nonoccupant. In nine trafficfatalities, find the probability that thenumber, Y, which involve an intoxicated oralcohol-impaired driver or nonoccupant is

a. exactlythree; at leastthree; at most three.

b. between two and four, inclusive.

c. Find and interpret the mean of the random variable Y.

d. Obtain the standard deviation of Y.

15 Researchers collected information on the body parts of a new species of frog. The thumb length for the female frog has a mean of 5.52 mm and a standard deviation of 0.55 mm. Let x denote thumb length for a female specimen.

a. Find the standardized version of x.

b. Determine and interpret thez-scores for thumb lengths of 6.1 mm and 4.3 mm. Round your answers to two decimal places.

a. Find the standardized version of x.

z= ( ? )

(Do not simplify. Use integers or decimals for any numbers in the expression. Do notround.)

b. Determine and interpret thez-scores for thumb lengths of 6.1 mm and 4.3 mm. Round your answers to two decimal places.

Determine and interpret thez-score for a thumb length of 6.1 mm.

Thez-score for a thumb length of 6.1 is ( ? ) This is ( ? ). standard deviations . below above

the mean thumb length.

(Round to two decimal places asneeded.)

Determine and interpret thez-score for a thumb length of 4.3 mm.

Thez-score for a thumb length of 4.3 is ( ? ) This is ( ? ) standard deviations ( below or above ? )

the mean thumb length.

(Round to two decimal places asneeded.)

12 The quantitative data set under consideration has roughly abell-shaped distribution. Apply the empirical rule to answer the following question.

A quantitative data set has mean 22 and standard deviation 4. Approximately what percentage of the observations lie between 18 and 26?

Approximately ( ?) % of the observations lie between 18 and 26.

(Type an integer or a decimal. Round to one decimal place asneeded.)

7 Construct astem-and-leaf diagram for the accompanyingdata, using two lines per stem.

23

32

36

21

46

29

49

47

39

40

48

36

47

26

28

33

41

31

26

36

6 What doesChebyshev's rule say about the percentage of observations in any data set that lie within

a. four standard deviations to either side of themean?

b. 2.5 standard deviations to either side of themean?

a. According toChebyshev's rule, at least What doesChebyshev's rule say about the percentage of observations in any data set that lie within

a. four standard deviations to either side of themean?

b. 2.5 standard deviations to either side of themean?

a. According toChebyshev's rule, at least ( ? ) % of the observations in any data set lie within four standard deviations to either side of the mean.

(ANSWER AS integer or decimal rounded to two decimal places asneeded.)

b. According toChebyshev's rule, at least ( ? ) % of the observations in any data set lie within 2.5 standard deviations to either side of the mean.

(ANSWER AS an integer or decimal rounded to two decimal places asneeded.)